#include <stdio.h>
// #include <stdlib.h>
// #include <time.h>
#include <string.h>

void zhuanhuan(char *ch,int len){
    for(int i=0;i<len;i++){
        if('A' <= ch[i] && ch[i] <= 'Z'){
            ch[i]+=32;
        }
        else if('a' <=ch[i] && ch[i] <= 'z'){
            ch[i]-=32;
        }
    }
    return;
}

int main(int argc,const char* argv[])
{   
    char ch[]="ABCDefgh";
    zhuanhuan(ch,strlen(ch));
    printf("转换后的字符串:%s\n",ch);;
    return 0;
}